I just launched a new project at codeplex aiming at the integration of jQuery UI in DotNetNuke: http://jquidnn.codeplex.com/. The first releases are already available in form of DNN module packages containing the core functionality, including infrastructural code to include jQuery and jQuery UI, two web controls for the Tabs and Datepicker widgets, and the smoothness theme.
Also available are module packages for three more themes: Cupertino, UI Darkness and UI Lightness. Further skins are actually quite easy to package and will follow over time, or when someone issues a request for one 
So please, start grabbing the releases and giving me feedback.